1. Field of the Invention
This invention relates to a method and an apparatus for equalizing airflow and/or airflow velocity from one or more air supply ducts to a plurality of discharge outlets. Such apparatus is useful in air conditioning and heating systems where equal airflows are desired at a plurality of discharge openings.
2. Description of the Prior Art
Conventionally, dampers or airflow splitters are used in an attempt to equalize the airflow velocity at a plurality of discharge outlets connected to an air duct. These devices produce widely varying airflow at the discharge outlets. For example, where the number of discharge openings is more than 100 in a duct device of drying equipment using passive distribution devices, an airflow velocity of 1 m/sec at each discharge outlet cannot be obtained if the average air duct airflow velocity is for example 10 m/sec. The reason for this is that the pressure loss from a damper or a splitter used to equalize air distribution in the air duct is (0.5 to 5 mm Ag).times.100=50 to 500 mm Ag. In addition, a vortex of airflow increasingly occurs as the distance from the air source becomes greater, thus making it more difficult to supply uniform air distribution to the discharge outlets.